It is known that ethanol interferes with the secretion of growth hormone (GH). Some alcoholics during withdrawal have a severely impaired GH response to insulin induced hypoglycemia. Other effects include a depression of plasma GH levels following acute alcohol administration and increased circulating GH levels in cirrhotic patients. At a cellular level there are still many unanswered questions concerning the mechanism of action of various growth factors. We have previously shown that in hypophysectomized animals GH is unique among the hormones tested by causing an increase in the (NADP+)/(NADPH) ratio in liver. This is relevant when considering the metabolic effects of ethanol as another study has shown a transient decrease in the (NADP)/(NADPH) ratio in liver following ethanol administration. Whether other growth factors may induce similar changes and the mechanism by which such changes are brought about are questions that merit investigation. At present, as a preliminary to the biochemical investigations, some active fragments of GH are being prepared by recombinant DNA techniques. By this means the problem of contamination of GH preparations by other active hormones will be overcome.